Problem: If $x \circledcirc y = 4x-7$ and $x \triangleright y = 5x+y$, find $(2 \triangleright -3) \circledcirc -1$.
Solution: First, find $2 \triangleright -3$ $ 2 \triangleright -3 = (5)(2)-3$ $ \hphantom{2 \triangleright -3} = 7$ Now, find $7 \circledcirc -1$ $ 7 \circledcirc -1 = (4)(7)-7$ $ \hphantom{7 \circledcirc -1} = 21$.